Ribbon feeding mechanism



Nov. 5, 1968 MAKOTO OKUDA RIBBON FEEDING MECHANISM 3 Sheets-Sheet 1 Filed April 26. 1966 V INVENTOR MA )1 0 TO OKUDA 91%% M FM 4 Nov. 5, 1968 MAKOTO OKUDA 3,409,114

RIBBON FEEDING MECHANISM Filed April 26, 1966 3 Sheets-Sheet 2 INVENTOR MA K0 T0 O/(UDA Fam 16 Wwk A r s Nov. 5, 1-968 MAKOTO OKUDA 3,409,114

RIBBON FEEDING MECHANISM Filed April 26, 1966 5 Sheets-Sheet 3 Fig. 5

INVENTOR NAKO T0 O/fl/OA BY M9 ?mi United States Patent 3,409,114 RIBBON FEEDING MECHANISM .Makoto Okuda, Osaka, Japan, assignor to Maruzen Sewing Machine Co. Ltd., Osaka, Japan Filed Apr. 26, 1966, Ser. No. 545,429 9 Claims. (Cl. 197-151) ABSTRACT OF THE DISCLOSURE Frictional drive means for an ink ribbon spool including a stud, a plate fixed on a ratchet mounted for rotation on-the stud, a disc having an annular flange and mounted for rotation on the stud, and a pair of U-shaped members slideably supported on the plate but rotatable therewith. Each U-shaped member has an arcuately shaped friction element, with spring means connected to the members normally urging the friction elements into driving engagement with the inner surface of the flange. A ribbon spool is detachably mounted for rotation on the stud and has means forming a positive rotary driving connection with the disc.

This invention relates to an ink ribbon feeding mechanism for computers, typewriters and the like and more particularly to an improved frictional drive means for the ribbon feeding mechanism.

One of the objects of this invention is the provision of an improved form of frictional drive means for one of the two ribbon spools of a ribbon feeding mechanism in which the drive means affords a positive driving connection to drive said one spool in one direction to wind up the ribbon and also permits unwinding of the ribbon from said spool when the ribbon is caused to move in an opposite direction.

Other objects and features of the present invention will be apparent from the following detailed description, reference being had to the accompanying drawing in which:

FIG. 1 is a right side elevational view of the printing mechanism of a computing machine embodying the present invention with a frame member removed to show the operating parts.

' FIG. 2 is a top plan view of the printing mechanism of FIG. 1;

FIG. 3 is a top plan view, on an enlarged scale, of the principal parts of the mechanism shown in FIG. 2, with the left and right hand spools removed to show the driving mechanism for said spools.

FIG. 4 is a cross sectional view, on an enlarged scale, taken substantially on line 44 of FIG. 2.

FIG. 5 is a cross sectional view, on an enlarged scale, taken substantially on line 55 of FIG. 2, and

FIG. 6 is an exploded perspective view of the left hand side spool driving means, illustrating my invention.

My invention is illustrated in the drawing as embodied in a computing machine of a well-known type and only so much of the machine as is required for a full understanding' of the present invention will be described.

. Referring to the drawing, the machine includes a pair of parallel side frame members 1 in which is supported a shaft 5 carrying a plurality of freely rotatable type sectors 6. A platen 8 is disposed rearwardly and above said sectors 6 and is rotatably supported between arms 7 which are rockably supported on the frame members 1. The arms 7 are. connected by means of links 4 to an actuating plate 3 fiXed on main shaft 2. As will be apparent rocking of shaft 2 in a counterclockwise direction, as viewed in FIG. 1, will effect rocking of the platen 8 in a direction to engage the type elements 70 of the type seetors 6. A pair of flanges 9 and 10 extending rearwardly from a rear frame member are disposed at opposite ends of the platen 8. A first spool 13 is mounted on a stud 11 fixed on flange 9 and a second spool 14 is mounted on stud 12 fixed on flange 10. A length of inking ribbon 15 is wound on the spools 13 and 14 at its both end portions and is guided into proper typing position in relation to the sectors 6 and platen 8 by ribbon guides 17 and 18 carried on arms 16 and 16, respectively, which are pivotally supported at suitable points on respective frame members 1. The ribbon 15 is tensioned by guide rollers 20 and 21 in order to eliminate slack which is caused when the ribbon is moved an incremental distance in response to the actuation of the main shaft 2. The roller 20 is supported on a rocker plate 22 which is biased by a spring 25 and limited in its rocking motion by a slot 23 cooperating with a pin 24. The roller 21 is fixed to horizontal plate 10.

Referring to FIG. 4 a sleeve 26 having an enlarged diameter portion 27 at its lower end is supported on stud 11 and is adapted to be locked into position against axial movement by a C-washer 30 engaged in an annular recess at the upper end of stud 11. The enlarged portion 27 of the sleeve 26 has fixed to its lower end a first driving ratchet wheel 28 from which extends a vertical stud 29 adapted to engage in one of a series of annularly arranged apertures 31 in the lower flange of spool 13, each aperture having a marginal extruded cylindrical flange. The sleeve 26 and spool 13 are thereby locked to each other for simultaneous rotation. A lever 42 pivoted on the upper flange of the spool 13 is adapted to engage in an annular recess at the upper end of the sleeve 26 to lock the spool in assembled relation to the sleeve 26.

A bell crank level 32 is pivotally supported on the lower end of the stud 11 intermediate the ratchet wheel 28 and the flange 9. One arm of lever 32 is connected to driving link 41 which is operatively connected to main shaft 2 whereby movement of the shaft will impart reciprocating motion to the driving link. The other arm of the bell crank lever 32 has a V-shaped plate 33 riveted thereto by spacing studs 34 and has an elongated slot 36 formed therein in registry with a correspondingly shaped slot 35 formed in said arm. A double acting pawl 37 is provided with sidewardly projecting ears 38, 38 which project through the slots 35 and 36 respectively, so as to be guided therein, the pawl 37 being held in engagement with the teeth of ratchet wheel 28 by a looped wire spring 40, one end of which is hooked about one of the spacing studs 34 and the other end of which is formed to gggage in a centrally located slot 39 formed in the pawl As the main shaft 2 is oscillated the bell crank lever 32 is caused to be swung back and forth, and the pawl 37 will therefore drive the ratchet wheel 28 in a direction depending on the position of the pawl. FIGS. 2 and 3 illustrate the two different positions which the pawl is capable of assuming. With the pawl 37 disposed in the position illustrated in FIG. 2, the spool 13 will be caused to rotate in a counter-clockwise direction and with the pawl 37 disposed in the position illustrated in FIG. 3 the spool will be caused to rotate in a clockwise direction.

A detent lever is pivoted on the flange 9 and has a sidewardly bent lug 76 engageable with the toothed periphery of the ratchet wheel 28, the lug being held in engagement with the periphery by a suitably anchored tension spring 73. The restraining force applied to the ratchet wheel 28 by the detent lever 75 is suflicient to hold the ratchet wheel against movement as the pawl 37 slides over the teeth of the ratchet wheel in non-driving direction but it is not suflicient to cause the pawl 37 to change its position to reverse its direction of drive. The direction of drive is changed upon a change in the direction of inclination of the pawl 37, in a manner as will be hereinafter explained.

The second spool 14 is mounted on a sleeve 53 supported on stud 12, the sleeve having fixed to its lower end a friction drum 52 having a downturned annular flange. The drum is provided with a series of spaced annularly arranged apertures 56 for the reception of the extruded cylindrical flanges 57 of the spool 14 which is the same construction as the spool 13. The upper end of the sleeve 53 is provided with an annular recess 54 to receive a pivoted lock element 58 of the spool whereby to lock the spool to the sleeve. A C-washer 55 adapted to engage in an annular recess in the stud 12 serves to lock the sleeve to the stud 12.

A ratchet wheel 44 is mounted on the enlarged lower portion of the stud 12 and has fixed thereto a plate 43 which carries a pair of headed studs 45 and 45 riveted to the plate. The heads of said studs are spaced from the plane of the plate 43 as will be seen clearly in FIGS. and 6. A pair of identical generally U-shaped friction members 47 and 47' are arranged in opposed relation as .illustrated in FIG. 6. One of the legs 77 and 78 of each of the friction members 47 and 47 respectively is offset from the plane of the member and each of the legs terminates in an outwardly bent portion which is pierced to receive one end of a spring 50, two such springs 50 and 50' being provided. Centrally of the bight portion of each of the members 47 and 47' there is provided an open ended slot 49, 49 and secured to the bight portions are arcuate friction elements 51 and 51'. In assembled relation an offset leg 77, 78 of one member lies contiguous to the planar leg of the opposite member and the slots 49, 49' resceive respective studs 45, 45 with the enlarged head portion of each stud overlying the marginal area of each of the slots. A washer 46 is disposed between the legs of the friction members and together with the cooperating slots and studs serves to guide the friction members in their movement. As will be apparent by reference to FIG. 5 the friction members 47 and 47 are confined within the space of the drum 52 with the friction elements 51, 51' engaging against the inner annular surface of the flange, the members 47, 47 being biased in an outwardly direction by the springs 50, 50. The spool 14 is supported on the drum 52 with the extruded flanges of the apertures 57 in the flange of the spool in engagement with the apertures 56 of the drum 52.

A pawl 59 operatively connected to the main shaft 2 whereby it is reciprocated upon rotation of the main shaft, is engaged with the teeth of the ratchet wheel 44 and is urged into such engagement by a pivoted arm 61 which is biased by a spring 64. The end of arm 61 is bent up and is notched as at 62. A detent pawl 63 is disposed on the opposite side of the ratchet wheel 44 and is biased by spring 64 in a direction to engage the ratchet wheel 44 and to prevent clockwise movement of the ratchet wheel 44.

Referring to FIG. 3 it will be seen that movement of the pawl 59 in a forward direction, downwardly as viewed in FIG. 3, will effect rotation of the ratchet wheel 44 and with it the plate 43 in a counterclockwise direction. Since the friction elements 51 and 51' are frictionally engaged with the interior surface of the flange of drum 52, the spool 14 is positively driven in a corresponding counterclockwise direction with ratchet wheel 44. The relatively weak tension springs 50 and 50 urging the members 47 and 47' outwardly so that the friction elements 51 and 51 engage against the inner surface of the flange of drum 52 afford the desired pressure for the transmission of torque from members 47, 47 to the drum 52. Correspondingly,'this relatively weak tension minimizes wear on the friction elements 51 and 51'.

In operation, the bell crank 32 and the pawl 59 function upon each operating cycle of the main shaft 2 to drive their respective ratchet wheels 28 and 44 as hereinbefore explained.v Assuming thatthepawl .37, is .in .the position illustrated in FIG. 2, rearward movement of the link 41 effected when the .main shaft 2 is rocked in a counterclockwise direction, as viewed in FIG. 1, corresponding to the forward stroke of the operating handle, effects rotation of the ratchet wheel 28 in a counterclockwise direction, as viewed in FIG. 2. correspondingly, the pawl 59 moving in a forward direction effects rotation of the ratchet wheel 44 in a counterclockwise direction, thereby causing the second spool 14 which is frictionally connected to the ratchet wheel 44 to wind up the ribbon 15 from the first spool 13. In the foregoing operation the ratchet wheel 28 in rotating in a counterclockwise direction, as viewed in FIG. 3, unwinds a predetermined length of ribbon 15 from spool 13 so that spool 14 which is frictionally driven may easily wind up this length of ribbon. The ribbon thus continues to be wound onto spool 14 until it is completely wound thereon but the end of the ribbon continues to be attached to spool 13. When the ribbon is completely unwound from spool 13, further rotation of ratchet wheel 28 is prevented by the restraining tension of the ribbon itself. Upon counterclockwise swinging movement of the bell crank 32, in the next cycle of operations, the pawl 37 will be forced upwardly in the slot 36 against the force of the spring 40 and will be moved from the position illustrated in FIG. 2 to the position illustrated in FIG. 3. Following this reversal of pawl 37 the pawl will thereafter in each cycle tend to drive the ratchet wheel 28 in a clockwise direction, as viewed in FIG. 3, thus tending to unwind the ribbon from spool 14 and to wind the ribbon onto the spool 13. It will be understood that in such winding of the ribbon the frictional resistance between the elements 51, 51 and the drum 52 is overcome so that the spool 14 may be unwound since the ratchet wheel 44 is locked against rotation by the detent pawl 63.

Upon the complete unwinding of the ribbon 1-5 from the spool 14, the restraining tension of the ribbon itself again effects a change in inclination of the pawl 37 so that ratchet wheel 28 now is caused to rotate in a counter-clockwise direction, as viewed in FIG. 3 to unwind a section of ribbon so that it may be wound on spool 14 which now is driven in a counter-clockwise direction, as viewed in FIG. 2.

It will be understood that the direction of rotation of ratchet wheel 44 is always in a counter-clockwise direction, as viewed in FIG. 3, and that the direction of the rotation of the spool 14 in winding of the ribbon on the spool is in the same direction. However, upon unwinding of spool 14, the ratchet wheel 28 which is caused to change its direction of rotation according to the direction of inclination of pawl 37, upon being caused to rotate in a clockwise direction as viewed in FIG. 3, will rotate spool 13 clockwise and through tension on the ribbon will effect rotation of the spool 14 in a direction to unwind the ribbon. This, of course, is accomplished by reason of slippage of the friction means hereinabove described.

In the printing or typing operation the platen 8 is caused to rock from the solid line position to the dotted line position illustrated in FIG. 1 so as to press the web of paper 71 wrapped around the platen against the ribbon which in turn is pressed against the type elements of the type sectors 6. This operation takes place upon each cycle of operation of the machine. It will also be understood that conventional means are employed for advancing the paper web with each cycle of operation so that typing is effected in columnar arrangement on the tape.

Various changes coming within the spirit of my invention may suggest themselves to those skilled in the art; hence, I do not wish to be limited to the specific embodiments shown and described or uses mentioned, but intend the same to be merely exemplary, the scope of my invention being limited only by the appended claims.

I claim:

1. In a ribbon feeding mechanism, the combination of a stud, a driving wheel including a plate mounted for rotation on said stud, a pair of friction members slidably supported on said plate but locked thereto for rotation therewith, a drum including a disc and an annular flange and mounted for rotation on said stud, means urging said friction members outwardly into frictional driving relation with the inner surface of said flange, and a ribbon spool detachably mounted for rotation on said stud and having means forming a positive rotary driving connection with said drum.

2. The invention as defined in claim 1 in which the driving wheel includes a ratchet wheel.

3. The invention as defined in claim 1 in which each of the friction members includes an arcuately shaped friction element in engagement with the inner surface of the flange.

4. The invention as defined in claim 1 in which the friction members are generally U-shaped and are arranged with the legs of one member in superposed relation to the other and with the bight portion disposed outwardly.

5. The invention as defined in claim 4 in which each of the friction members includes an arcuately shaped friction element in engagement with the inner surface of the flange.

6. The invention as defined in claim 5 in which the plate carries a pair of fixed studs for guiding the movement of said U-shaped members.

7. The invention as defined in claim 4 in which the means urging the friction members outwardly comprises a pair of tension springs connected to the legs of said U-shaped members.

8. The invention as defined in claim 1 in which the drum includes a sleeve fixed to the disc and mounted for rotation on said stud.

9. The invention as defined in claim 6 in which the studs are formed with enlarged overhanging heads to confine and guide said U-shaped members and in which said heads aflord spacing means to space said friction elements from the inner surface of said disc.

References Cited UNITED STATES PATENTS 2,972,402 2/1961 Howard 197165 ROBERT E. PULFREY, Primary Examiner.

E. T. WRIGHT, Assistant Examiner. 

